A three-story warehouse on Capitol Hill—reputedly a bakery in the early 1900s—was carved into six apartments in the 1970s. It was left untouched until 2017, when a couple rescued the 4,000-square-foot diamond in the rough, hiring DC’s Architrave P.C. Architects to transform it into a livable loft. Avid design buffs, pediatrician Eric Rosenthal and Jeffrey Menzer, a public health consultant, envisioned the home as an edgy, industrial-style backdrop for their collection of Mid-Century Modern furniture, ceramics and art.

The architects gutted the place, preserving exposed-brick walls, concrete floors and unfinished wooden ceilings. They created a three-story tower near the stairs that connect the three levels; it houses utility spaces and cozy hangouts in the otherwise airy abode.

In 2019 while construction was still underway, the owners tapped designer Nicole Lanteri to mastermind the interiors. Curating a trove that includes iconic pieces by Frank Gehry, George and Mira Nakashima and Eileen Gray, she and her clients feathered the now-complete nest with a heady mix of new and vintage furniture and exquisite textiles. A lively color palette and quirky spirit bring new life to a relic that time forgot. A Q&A details the process.

What was most genius about Architrave’s makeover?
When you start to open things up, a home can feel cavernous and not proportional to how you live. But they created cozy areas amid open, unstructured spaces. Orienting everything around a center stair column was beautiful because it lets light in as you come up the staircase and provides an element of surprise at each turn. I also like how they owned the building’s imperfections—like the family room’s concrete floors—and worked around them.

Explain your goals from the get-go.
A few rooms were darker than Eric and Jeffrey anticipated, so brightening them up was important. They wanted color and also wanted to be able to host a lot of people in the public spaces.

Describe the vibe you were after.
I’d call the overall style Mid-Century Modern meets Japanese loft.

Detail how the design phase unfolded.
We started with the dining room because they had the Nakashima table and Risom chairs. We met a couple times a month and showed them a few more pieces each time, while Jeffrey searched out vintage items. The process, which took about a year, had a nice rhythm. It felt like we were collecting on a purposeful timeline.

Share techniques that helped avoid a cavernous feel.
I used layers to ground the space and counteract the tall, unfinished ceilings. We started with rugs that have a nubby texture. We were able to use a lot of large, soft furnishings without worrying about things feeling too upholstered because of the raw finishes everywhere. In the living room, the Moroso poufs have the same effect as a sweater; there’s a handmade quality to them.

What impressed you about your clients’ art and accessories?
I couldn’t have asked for a better collection. Their things are not fancy—it’s just stuff they like. You need meaningful objects to make a place feel like a home.

How much of the furniture is new?
About 80 percent is new, much of it from M2L. When we bought new, they were forever pieces. About 70 percent of the lighting, accent chairs, art and pottery is vintage, from the owners’ collection or newly purchased.

Why do vintage pieces add character to interiors?
There’s a patina and warmth that’s unique to every piece; each has its own identity. They talk to each other and bring in a bit of quirkiness. For example, the vintage Frank Gehry chairs have a sculptural quality, almost like works of art.

Define your philosophy on bringing color into the home.
I often find myself pushing clients to choose more color. But when they really love it, I have to explain that it can be too attention-grabbing. Eric wanted things to be super-colorful and kind of out there; we had to pare things back a little to find the right balance.

Reveal your current paint color crush. 
Backdrop, a maker of sustainable paints, has a new shade called Cake Shop. It’s a periwinkle that would look amazing with red, gray or blue.

Share a product you're excited to check out. 
Marrimor, a Massachusetts atelier, sent me details on their Draft Rug line. The carpets are irregular and organic in shape; I’ve never seen anything like them.

What piece in your home will you never part with?
Our dining table. My husband and I got it in a New York vintage shop when we were in our 20s. Stained ebony with curvy legs, it’s now paired with modern Eames chairs.

Name a film or TV set that resonated with your inner designer. 
In "The King’s Speech" starring Colin Firth, the walls in a distressed paisley pattern were so cool. They looked like someone had peeled off wallpaper and found another layer.